1. Field of the Invention
The present invention relates to a liquid crystal projector with an illuminating light collecting unit which can efficiently collect illuminating light emitted from a lamp of the projector to a scrambler.
2. Description of the Related Art
In general, a projector serves to enlarge a small image displayed on a cathode ray tube or a liquid crystal display panel to a large image by using direct or indirect projection technique through an optical instrument so that the large image is projected onto a screen.
The direct projection technique is referred to as a forward projection and the projector which is used therefor is disposed separately from a cabinet in order to project the image directly onto a screen.
The indirect projection technique is referred to as a backward projection and the projector forming the optical instrument is disposed inside the cabinet so that illuminating light is projected onto the screen via a reflection mirror which is disposed to face backward.
FIG. 1 shows a conventional device in connection with the optical elements employed at the projector.
In FIG. 1, illuminating light la emitted from a lamp 1 is reflected by a hemisphere-shaped reflector 2 and is directed into a rod-shaped scrambler 3 which is made of glass thereby to be passed therethrough. Subsequently, the illuminating light 1a is projected onto the screen to be enlarged via a projection lens or a liquid crystal display panel not shown.
The conventional optical device uses a Metal Halide Lamp 1 which operates by an arc discharge as a light source.
As shown in FIG. 2, however, when illuminating light 1a emitted from the lamp 1 passes the scrambler 3, the position of the light 1a being collected or converged to the scrambler 3 may minutely fluctuate at a longitudinal or transverse direction due to an arc sparking thereby causing an increase of the loss of light.
This causes the brightness of the screen to be changed.